Electromagnet-coil construction.



M. J. WOHLKS; H. HERTZBERG.

LEGTROMAG-NET COIL CONSTRUCTION.

'APPLIOATION FILED Nov.18,19oa.

@i u atente; Aug; 1'?, i909.

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.that thel insulation will not be destroyed by "the heat generated inthe coil by the passage .winding` turns ot bare aluminum wire z ller-Unirnn siti-iras rarest MAURICE J. WOHL, OF NEW YORK, AND HARRYHERTZBERG, OF BROOKLYN, NEW YORK, AtjJGNORS TO ABBOT A. LOW, OFHORSESIIOE, NEW YORK, MAURCE J. WOHL, OF

YORK, N, Y., AND HARRY HERTZBERG, OF BROOKLYN, NEW YORK, TRUSTEES.

ELECTROM G NE T-OOIL CONSTRUCTION.

To all whom it may concern:

Be it known that we, Maintien J. lilVonL and i-ixnav -lnn'rznnno,citizens ot' the United States, and residents, respectively, otl thecity ot New York, borough ot` idanhattan, county and State ot New York.,and of the city otx New York, borough ot' Brooklyn, county of Kings, andState of New York, have invented certain new and useful Improvements inElectromagnet-Coil Construction, of which the following,` is aspeciiication;

This in\ 'ention relates .o elect-romagnet coil construction and has'for itsl object the provision ot means for insulating` the turns ot'wire trom one another in such a manner of the currenttherethrough orotherwise.

The object of the invention is to avoid the difficulty experienced inelectroinagnet coils in which the ordinary insulating wire is used otthe insulation being destroyed when the coil excessively heated.

- It further object ot the invention to simplify and cheapen the coilconstruction by en'iploying bare wire instead ot the usual insulatedwire. l

in the drawing acconipanyingthis specitication like parts in the severalviews have Figure l a side elevation, partly in sec tion, showingv theseveral layers of wire in position. Fig. l is a view similar to Fig. l,showing` the coil after the saine has been in use. Fig'. 23 shows thecouumsite insulating strip. V

A. spool upon which the electromagnet coil wound is shown at l. rThisspool may be ot' any approved eonstruetiou and upon the same ,is woundsuccessive turns ot the conductor for the operating current, preferablyof copper wire, as shown at Between these successive turns ot theconducting winding positioned successive turns of an insulator. Thisinsulator is lshown in the drawing at 3 and preferably t'ormcd by nateiywith the turnsI ot the couductiue'l wire 2.

he aluminum wire oxidizes readily when exposed to the air, especially itsome uioisi Specification of Letters Patent.

Application tiled November 1B, 1998.

Patented Aug. 17, 1909.

serial No. 463,235.4

ture is present, and the oxidation is accelerated when the wire isheated. This forms an insulatingr coating of oxid for the aluminum wirehaving sullicient insulating properties to insulate the successive turnsof the conducting wire 2 troni one another. It is understood inelectromagnet coil construction for any ordinary purposes that thedifterence in potential or drop between two successive turns of the coilis very small and it has been found by actual tests that a coil woundwith bare wire for the conducting winding and having alternateiypositioned therewith turns ot bare aluminum wire with coating ot oxid,as described, will operate successfully and will possess the verydesirable property ot being able to withstand ef;- cessive heating`faused by an unusual amount 7b of current or from other sources withoutbreaking down. In fact the effect ot' the heating. as already explained,is to accelerate and increase the formation of the insulatinp, coatingof oxid.

vWhere the coil is composed oit a plurality oi layers of winding,theselayers may be insulated Yfrom one another by interposinf.)r betweenthe saine a strip ot insulating inaterial. This is preferably acomposite strip comprising a central layer of mica and outer layers ot acombustible material, such as paper or cloth. Such a strip is shown inFig'. 3. x

rlhe mica torms a goed insulator, but is so brittle that it ispractically impossible to wind or place the same in position upon thesuccessive layers of wire but by using a coinposite. strip constructedas described, this is easily accon'iplished as the strip in ay be Si)readily wound upon the successive layers of wire, as shown in thedrawings.

tui-ther advantage obtained by using a composite insulating strip suchas described that when the coil becomes heated the outer layers l'ieiugvoit combustible nlaterial burn away leaving the layer of inicain place.This provides an additional space which permit-s the turns of thewinding to become separated somewhat, thus increasii'g'uo" the.insulating elt'ect. Y

Fig. l shows a coil such as described betorc use and Fit'. 2 shows thesame. coil after the saine has been used and heated. aud the is A i931,541

combustible layers burned away from the strip between the layers of thewinding, the eectbeing, of course, somewhat exaggerated vin mler to showthe separation of the turns of the Winding, etc., in the drawing.

It will be understood that the foregoing description and drawing areintended to show a preferred embodiment of the invention for thepurposes of illustrating the same and the insulator or insulatingwinding has been described as aluminum wire which is oxidized on itssurface. It is not to be understood, however, that the invention islimited in this respect to any particular material or to the particularform of coil or Winding shown and described, as it Will be evident thatmany changes may be made in the details of construction shown anddescribed wlithout departing from the scope of the invention.

What We claim is:

1. An electromagnet coil Wound with alternate turns of copper Wire andaluminum Wire.

2. The method of making an electromagnet coil which consists in Windingalternate turns of bare Wire, one forming a conductor for the currentpassing through the coil and the other forming an insulator between thesuccessive turns.

3. An electromagnet coil comprising a plurality of layers, each layerhaving successive turns of a conducting Winding alternately positionedwith successive turns of an insulator, and a compositestrip located between said layers comprising a central layer of insulating material andouter layers of combustible material.

l. The method of making an electromagnet coil which consists in Windinga pluralit-y of layers, each layer having successive turns of aconducting winding alternately positioned With'successive turns of aninsulator, and successively Winding upon said layers a composite stripcomprising a central layer .of insulating material and outer layers ofcombustible material.

Signed at Brooklyn, N. Y. city, in the county of Kings and State ofNeWYork, this 16th day of November, 1908.

A. LAURENT, Grao. TELLING GIDnrNos.

